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Clean up the lossless JPEG feature

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- Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the
  function so that it stores the lossless parameters directly in the Ss
  and Al fields of jpeg_compress_struct rather than using a scan script.

- Move the cjpeg -lossless switch into "Switches for advanced users".

- Document the libjpeg API and run-time features that are unavailable in
  lossless mode, and ensure that all parameters, functions, and switches
  related to unavailable features are ignored or generate errors in
  lossless mode.

- Defer any action that depends on whether lossless mode is enabled
  until jpeg_start_compress()/jpeg_start_decompress() is called.

- Document the purpose of the point transform value.

- "Codec" stands for coder/decoder, so it is a bit awkward to say
  "lossless compression codec" and "lossless decompression codec".
  Use "lossless compressor" and "lossless decompressor" instead.

- Restore backward API/ABI compatibility with libjpeg v6b:

  * Move the new 'lossless' field from the exposed jpeg_compress_struct
    and jpeg_decompress_struct structures into the opaque
    jpeg_comp_master and jpeg_decomp_master structures, and allocate the
    master structures in the body of jpeg_create_compress() and
    jpeg_create_decompress().

  * Remove the new 'process' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with the old
    'progressive_mode' field and the new 'lossless' field.

  * Remove the new 'data_unit' field from jpeg_compress_struct and
    jpeg_decompress_struct and replace it with a locally-computed
    data unit variable.

  * Restore the names of macros and fields that refer to DCT blocks, and
    document that they have a different meaning in lossless mode.  (Most
    of them aren't very meaningful in lossless mode anyhow.)

  * Remove the new alloc_darray() method from jpeg_memory_mgr and
    replace it with an internal macro that wraps the alloc_sarray()
    method.

  * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into
    jpegint.h.

  * Remove the new 'codec' field from jpeg_compress_struct and
    jpeg_decompress_struct and instead reuse the existing internal
    coefficient control, forward/inverse DCT, and entropy
    encoding/decoding structures for lossless compression/decompression.

  * Repurpose existing error codes rather than introducing new ones.
    (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain,
    although JWRN_MUST_DOWNSCALE will probably be removed in
    libjpeg-turbo, since we have a different way of handling multiple
    data precisions.)

- Automatically enable lossless mode when a scan script with parameters
  that are only valid for lossless mode is detected, and document the
  use of scan scripts to generate lossless JPEG images.

- Move the sequential and shared Huffman routines back into jchuff.c and
  jdhuff.c, and document that those routines are shared with jclhuff.c
  and jdlhuff.c as well as with jcphuff.c and jdphuff.c.

- Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where
  it is used.

- Move the predictor and scaler code into jclossls.c and jdlossls.c.

- Streamline register usage in the [un]differencers (inspired by similar
  optimizations in the color [de]converters.)

- Restructure the logic in a few places to reduce duplicated code.

- Ensure that all lossless-specific code is guarded by
  C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can
  be built successfully if either or both of those macros is undefined.

- Remove all short forms of external names introduced by the lossless
  JPEG patch.  (These will not be needed by libjpeg-turbo, so there is
  no use cleaning them up.)

- Various wordsmithing, formatting, and punctuation tweaks

- Eliminate various compiler warnings.
This commit is contained in:
DRC
2022-11-08 15:01:18 -06:00
parent ec6e451d05
commit 217d1a75f5
67 changed files with 3171 additions and 3871 deletions
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81
jccoefct.c
View File

@@ -2,20 +2,19 @@
* jccoefct.c
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1994-1998, Thomas G. Lane.
* Copyright (C) 1994-1997, Thomas G. Lane.
* Lossless JPEG Modifications:
* Copyright (C) 1999, Ken Murchison.
* Copyright (C) 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains the coefficient buffer controller for compression.
* This controller is the top level of the JPEG compressor proper.
* This controller is the top level of the lossy JPEG compressor proper.
* The coefficient buffer lies between forward-DCT and entropy encoding steps.
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jlossy.h" /* Private declarations for lossy codec */
/* We use a full-image coefficient buffer when doing Huffman optimization,
@@ -35,6 +34,8 @@
/* Private buffer controller object */
typedef struct {
struct jpeg_c_coef_controller pub; /* public fields */
JDIMENSION iMCU_row_num; /* iMCU row # within image */
JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
int MCU_vert_offset; /* counts MCU rows within iMCU row */
@@ -42,20 +43,20 @@ typedef struct {
/* For single-pass compression, it's sufficient to buffer just one MCU
* (although this may prove a bit slow in practice). We allocate a
* workspace of C_MAX_DATA_UNITS_IN_MCU coefficient blocks, and reuse it for
* each MCU constructed and sent. (On 80x86, the workspace is FAR even
* though it's not really very big; this is to keep the module interfaces
* unchanged when a large coefficient buffer is necessary.)
* workspace of C_MAX_BLOCKS_IN_MCU coefficient blocks, and reuse it for each
* MCU constructed and sent. (On 80x86, the workspace is FAR even though
* it's not really very big; this is to keep the module interfaces unchanged
* when a large coefficient buffer is necessary.)
* In multi-pass modes, this array points to the current MCU's blocks
* within the virtual arrays.
*/
JBLOCKROW MCU_buffer[C_MAX_DATA_UNITS_IN_MCU];
JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
/* In multi-pass modes, we need a virtual block array for each component. */
jvirt_barray_ptr whole_image[MAX_COMPONENTS];
} c_coef_controller;
} my_coef_controller;
typedef c_coef_controller * c_coef_ptr;
typedef my_coef_controller * my_coef_ptr;
/* Forward declarations */
@@ -73,8 +74,7 @@ LOCAL(void)
start_iMCU_row (j_compress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row */
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
/* In an interleaved scan, an MCU row is the same as an iMCU row.
* In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
@@ -101,8 +101,7 @@ start_iMCU_row (j_compress_ptr cinfo)
METHODDEF(void)
start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
coef->iMCU_row_num = 0;
start_iMCU_row(cinfo);
@@ -111,18 +110,18 @@ start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
case JBUF_PASS_THRU:
if (coef->whole_image[0] != NULL)
ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
lossyc->pub.compress_data = compress_data;
coef->pub.compress_data = compress_data;
break;
#ifdef FULL_COEF_BUFFER_SUPPORTED
case JBUF_SAVE_AND_PASS:
if (coef->whole_image[0] == NULL)
ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
lossyc->pub.compress_data = compress_first_pass;
coef->pub.compress_data = compress_first_pass;
break;
case JBUF_CRANK_DEST:
if (coef->whole_image[0] == NULL)
ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
lossyc->pub.compress_data = compress_output;
coef->pub.compress_data = compress_output;
break;
#endif
default:
@@ -145,8 +144,7 @@ start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
METHODDEF(boolean)
compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
JDIMENSION MCU_col_num; /* index of current MCU within row */
JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
@@ -178,10 +176,10 @@ compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
for (yindex = 0; yindex < compptr->MCU_height; yindex++) {
if (coef->iMCU_row_num < last_iMCU_row ||
yoffset+yindex < compptr->last_row_height) {
(*lossyc->fdct_forward_DCT) (cinfo, compptr,
input_buf[compptr->component_index],
coef->MCU_buffer[blkn],
ypos, xpos, (JDIMENSION) blockcnt);
(*cinfo->fdct->forward_DCT) (cinfo, compptr,
input_buf[compptr->component_index],
coef->MCU_buffer[blkn],
ypos, xpos, (JDIMENSION) blockcnt);
if (blockcnt < compptr->MCU_width) {
/* Create some dummy blocks at the right edge of the image. */
jzero_far((void FAR *) coef->MCU_buffer[blkn + blockcnt],
@@ -205,7 +203,7 @@ compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
/* Try to write the MCU. In event of a suspension failure, we will
* re-DCT the MCU on restart (a bit inefficient, could be fixed...)
*/
if (! (*lossyc->entropy_encode_mcu) (cinfo, coef->MCU_buffer)) {
if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
/* Suspension forced; update state counters and exit */
coef->MCU_vert_offset = yoffset;
coef->mcu_ctr = MCU_col_num;
@@ -248,8 +246,7 @@ compress_data (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
METHODDEF(boolean)
compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
JDIMENSION blocks_across, MCUs_across, MCUindex;
int bi, ci, h_samp_factor, block_row, block_rows, ndummy;
@@ -270,10 +267,10 @@ compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
block_rows = compptr->v_samp_factor;
else {
/* NB: can't use last_row_height here, since may not be set! */
block_rows = (int) (compptr->height_in_data_units % compptr->v_samp_factor);
block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor);
if (block_rows == 0) block_rows = compptr->v_samp_factor;
}
blocks_across = compptr->width_in_data_units;
blocks_across = compptr->width_in_blocks;
h_samp_factor = compptr->h_samp_factor;
/* Count number of dummy blocks to be added at the right margin. */
ndummy = (int) (blocks_across % h_samp_factor);
@@ -284,7 +281,7 @@ compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
*/
for (block_row = 0; block_row < block_rows; block_row++) {
thisblockrow = buffer[block_row];
(*lossyc->fdct_forward_DCT) (cinfo, compptr,
(*cinfo->fdct->forward_DCT) (cinfo, compptr,
input_buf[ci], thisblockrow,
(JDIMENSION) (block_row * DCTSIZE),
(JDIMENSION) 0, blocks_across);
@@ -345,8 +342,7 @@ compress_first_pass (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
METHODDEF(boolean)
compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef = (c_coef_ptr) lossyc->coef_private;
my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
JDIMENSION MCU_col_num; /* index of current MCU within row */
int blkn, ci, xindex, yindex, yoffset;
JDIMENSION start_col;
@@ -384,7 +380,7 @@ compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
}
}
/* Try to write the MCU. */
if (! (*lossyc->entropy_encode_mcu) (cinfo, coef->MCU_buffer)) {
if (! (*cinfo->entropy->encode_mcu) (cinfo, coef->MCU_buffer)) {
/* Suspension forced; update state counters and exit */
coef->MCU_vert_offset = yoffset;
coef->mcu_ctr = MCU_col_num;
@@ -410,14 +406,13 @@ compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)
GLOBAL(void)
jinit_c_coef_controller (j_compress_ptr cinfo, boolean need_full_buffer)
{
j_lossy_c_ptr lossyc = (j_lossy_c_ptr) cinfo->codec;
c_coef_ptr coef;
my_coef_ptr coef;
coef = (c_coef_ptr)
coef = (my_coef_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(c_coef_controller));
lossyc->coef_private = (struct jpeg_c_coef_controller *) coef;
lossyc->coef_start_pass = start_pass_coef;
SIZEOF(my_coef_controller));
cinfo->coef = (struct jpeg_c_coef_controller *) coef;
coef->pub.start_pass = start_pass_coef;
/* Create the coefficient buffer. */
if (need_full_buffer) {
@@ -431,9 +426,9 @@ jinit_c_coef_controller (j_compress_ptr cinfo, boolean need_full_buffer)
ci++, compptr++) {
coef->whole_image[ci] = (*cinfo->mem->request_virt_barray)
((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
(JDIMENSION) jround_up((long) compptr->width_in_data_units,
(JDIMENSION) jround_up((long) compptr->width_in_blocks,
(long) compptr->h_samp_factor),
(JDIMENSION) jround_up((long) compptr->height_in_data_units,
(JDIMENSION) jround_up((long) compptr->height_in_blocks,
(long) compptr->v_samp_factor),
(JDIMENSION) compptr->v_samp_factor);
}
@@ -447,8 +442,8 @@ jinit_c_coef_controller (j_compress_ptr cinfo, boolean need_full_buffer)
buffer = (JBLOCKROW)
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
C_MAX_DATA_UNITS_IN_MCU * SIZEOF(JBLOCK));
for (i = 0; i < C_MAX_DATA_UNITS_IN_MCU; i++) {
C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
coef->MCU_buffer[i] = buffer + i;
}
coef->whole_image[0] = NULL; /* flag for no virtual arrays */